"These scams are quite complex and on at least one occasion the scammer has known personal information about the victim."
Doell said police, or any other government agency, would never demand money or any other form of payment over the phone.
"If you think you've been scammed, we urge you to report [it] as soon as possible to your nearest police station and warn your friends and family so others in the community are also aware of this scam," Doell said.
People who receive suspicious calls should hang up immediately and not engage with the caller, police said.
Anyone with information or who has received similar calls is asked to contact the Financial Crime Unit on (09) 302 6400 or local police station.